1. Field of the Invention
The present invention relates to a structure for fixing a shoe to a bicycle pedal through a cleat attached to the bottom of the shoe.
2. Description of the Prior Art
FIGS. 19 and 20 show a known structure for fixing a shoe to a bicycle pedal through a cleat attached to the bottom of the shoe. Generally, a pedal shaft 43 rotatably supports a pedal body 44 including a front hook 44a formed on a front end thereof and having an engaging portion having approximately the same width as a front engaging portion of a cleat 45. The pedal body 44 also includes a rear hook claw 41 connected to a rear end thereof to be pivotable between an engaging position and a disengaging position. The rear hook claw 41 includes a cleat contacting portion 41a and a cleat engaging portion 41b extending axially of the pedal body 44. A spring 42 is mounted between the rear hook 41 and pedal body 44 to urge the rear hook claw 41 forwardly toward the engaging position. The cleat 45 includes a recessed engaging portion 45a at a rear end thereof for fitting engagement with the rear hook 41. Such a known structure is disclosed in the Japanese patent application laid open under No. 60-197478, for example.
When attaching the shoe to the pedal through the cleat 45, the cyclist moves the shoe obliquely downwardly and forwardly relative to the pedal body 44. After the front end of the cleat 45 is engaged by the front hook 44a of the pedal body 44, the cyclist places the rear end of the cleat 45 in contact with a guide portion of the rear hook 41. In this state, the shoe is pressed down, which causes the rear hook 41 to pivot rearwardly to the disengaging position against the force of spring 42. The rear end of the cleat 45 enters a position opposite a back face of the rear hook 41. Then, the rear hook 41 returns under the force of spring 42 and engages the rear end of the cleat 45. This engagement fixes the shoe to the pedal through the cleat 45.
When releasing the shoe from the fixed state, the cyclist turns the shoe about an axis perpendicular or approximately perpendicular to treads of the pedal, using the front end of the cleat 45 as a pivotal point. As a result of this pivotal movement, the rear hook 41 moves from a recess D defining the engaging portion 45a and mounts an adjacent non-recessed portion E. This causes the rear hook 41 to pivot rearwardly to the disengaging position against the force of spring 42, thereby releasing the shoe.
However, according to the known construction noted above, the shoe is releasable from the pedal only by turning the shoe about an imaginary axis perpendicular or approximately perpendicular to the treads of the pedal, using the front end of the cleat 45 as a pivotal point. With the known construction, therefore, the shoe may not be released from the pedal when, for example, the cyclist falls over to the ground and tilts the shoe sideways relative to the pedal treads.
Further, the rigid connection between the shoe and bicycle pedal, according to the prior art as noted above, applies a treading force of the cyclist to the pedal effectively and reliably. On the other hand, in the case of a mountain bike which runs rough terrains, such a connection transmits violent vibrations resulting from the roughness of the terrain to the cyclist's foot. The known connecting structure between the bicycle pedal and cleat includes engaging members attached to the pedal shaft for connection to the shoe, and the shoe rests on the pedal through the engaging members. Moreover, such engaging members are generally formed of a highly rigid material to assure a strong connection to the shoe. Thus, the vibrations due to the roughness of the terrain are transmitted directly to the cyclist's foot without being damped, thereby straining the cyclist's foot.
Even in an ordinary run of the bicycle, the torsional force about the imaginary axis noted above may be applied to the shoe connected to the pedal body. When cornering on a mountain bike, for example, the cyclist may pedal the bike with only one foot in an unstable posture. To maintain his balance in such a condition, the cyclist turns the pedal body while applying a torsional force about the above-mentioned imaginary axis to the shoe connected to the pedal body. Further, when the cyclist pedals the bicycle without being seated on the saddle, the unstable posture could result in an inadvertent application of a torsional force about the imaginary axis to the shoe connected to the pedal body. According to the known structure noted above, the shoe could inadvertently disengage from the pedal body under the torsional force applied to the shoe connected to the pedal body. The cyclist faces a serious danger as a result of the shoe disengaging from the pedal body while the cyclist is in such an unstable posture. To prevent the shoe from inadvertently disengaging from the pedal body, it is conceivable to set the torsional force for turning the shoe about the imaginary axis to a high level. However, such a measure would be inappropriate since the shoe would not readily be released from the pedal body in an emergency, such as when the cyclist falls over.
Moreover, according to the known structure noted above, the shoe must be turned a great extent about the imaginary axis to become disengaged from the pedal body. In an emergency such as when the cyclist turns over, the shoe turned a small amount only results in re-engagement between the cleat and engaging members. The cyclist could be seriously injured with the shoe remaining caught with the pedal body.